Project Summary Venous thromboembolism (VTE) manifests as deep vein thrombosis (DVT) of the leg and its complication, pulmonary embolism (PE). VTE is a major health problem with over 400,000 VTE events in the US annually. VTE costs more than $8 billion per year to our health care system and causes more than 100,000 deaths per year in the US alone. Despite administration of chemoprophylaxis to trauma patients during hospitalization, about 5% of patients still develop symptomatic VTE prior to discharge and more alarmingly, about 40-60% of patients develop symptomatic VTE after discharge. Hence, we need a personalized and individualized VTE risk score for acutely injured patients and to address the NIH initiative of defining the ?role of laboratory monitoring? to help better define those at risk of bleeding and thrombosis.? Our specific aims will address current gaps in knowledge by: (Aim 1) validation of a VTE risk prediction tool for the individual with acute trauma using clinical data, novel plasma biomarkers, and (Aim 2) to assess if addition of genotype data (i.e., F5 rs6025 [Factor V Leiden], F2 rs1799963 [Prothrombin G20210A], and ABO rs8176719 [non-O blood type]) improve the accuracy of the prediction tool. Successful completion of our study aims will provide a validated, generalizable, clinically-applicable risk assessment tool for stratifying risk of VTE in the individual trauma patient. This risk tool, which incorporates easily obtainable clinical risk factors, as well as the individual patient's prothrombotic phenotype and genotype, will more accurately predict the occurrence of symptomatic VTE after injury.